Congenital heart disease (CHD) is the most common congenital defect affecting approximately 1% of live births. Initially developed and optimized for adults, cardiovascular MRI (CMR) is increasingly used in pediatric CHD patients to complement echocardiography and invasive angiography for anatomical and functional evaluation of the heart and blood vessels. For children, the non-invasiveness, unrestricted field of view, lack of contrast nephrotoxicity and absence of ionizing radiation make MRI an attractive imaging modality, as many of the patients will likely need sequential imaging and follow-up in the long term. However, current CMR is limited by the breath-holding period, the need to capture the first-pass of a gadolinium (Gd) bolus and relatively thick 2D slices in cardiac cine MRI. Consequently, despite yielding exquisitely detailed information on extra-cardiac vascular anatomy, current CMR methods fall short of providing comparable definition of dynamic intra-cardiac anatomy, such as the cardiac chambers, valves, coronary arteries, and other pulsatile blood vessels, despite the fact that the status of these structures often determines the basis for treatment planning. We propose a new paradigm of CMR in pediatric CHD to address these issues. Completion of the project will result in the clinical deployment of a set of MRI pulse sequences, image acquisition and reconstruction strategies CMR in pediatric CHD patients, and successful validation in a cohort of patients of its diagnostic value.